Load-regulating system.



W. L. WATERS. LOAD REGULATING SYSTEM. APPLICATION FILED JULY 22. I914.

1,242,284. Patented Oct. 9,1917. I

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LOAD REGULATING SYSTEM.

APPLICATION man JULY 22.1914.

Patented Oct. 9,1917.

2 SHEETS-SHEET 2.

m6 nesse WILLIAM L. WATERS, 0F MILWAUKEE, WISCONSIN.

LOAD-BEGULATING SYSTEM.

Specification of Letters latent.

Patented Oct. 9, 191 '7.

Application filed July 22, 1914. Serial No. 852,512.

To all whom it may concern:

Be it known that I, WILLIAM L. WATERS, a citizen of the United States,residing at Milwaukee, in the county of Milwaukee and State ofWisconsin, have invented certain new and useful Improvements inLoad-Regulating Systems, of which the following is a full, clear,concise, and exact description, reference being had to the accompanyingdrawings, forming a part of this specification..

The subject-matter of this invention is a load regulating system.

A power generatin station can be operated at maximum efficiency onlywhen all the apparatus is operating continuously under full load. Thiscan be secured only where there is a constant demand for the entire loadof a station.

Consumers can secure the most favorable contract for purchasing power byconformtion which will maintain the rate of drawing energy from thesupply mains at or below a predetermined value.

In the drawings,

Figure 1 is a diagrammatic illustration of a system embodying myinvention;

Fig. 2 is a diagram of a further development of the same; and

Fig. 3 is a diagram of a modification.

A maximum demand limitation is a limitati'on upon the rate at which workis done, that is to say, on the rate of wattage consumed. This rate maybe controlled by con trolling either current or voltage.

In case the consumer receives electrical power in a form in which itmust first be transformed or translated before he can use it, it becomesimperative to limit the flow of energy into the transforming ortranslating devices when the load becomes a maximum. This could be doneby regulating the current or voltage of the electrical energy assupplied, but there are certain practical disadvantages or limitationsin doing this. Due to the economy of transmission, power is usuallydelivered in the form of hightension alternating-current. cult toregulate because of either the high voltage or the quantity of current.

My invention provides means for readily limiting the load taken by theconsumerwithout handling currents of excessive pressure or quantity andwith a minimum of waste. Instead of attempting to limit the current orthe voltage impressed on the transforming or translating devices, Iregulate the voltage of the transformed or translated energy, that is tosay, if the demand increases, I maintain the load upon the supply mainsconstant by decreasing the voltage of the consumption circuits.

This invention relates, not only to the control of the withdrawal ofelectric energy from the electrical supply mains, but is useful as wellfor the control of the rate at which the energy is drawn from anysimilar supply mains in such cases as it is desired to come within therequirements of a predetermined maximum. In many cases electricalgenerators or generating units are driven by steam or water power, whichpower is furnished under the limitation of a predetermined maximum. Insuch cases, the rate of drawing energy would be decreased by loweringthe voltage in the consumption circuits to keep the load within thepredetermined maximum.

In the following description the term transforming device will beunderstood to mean any means for transforming energy from one form intoanother. This term is intended to include the above types of units aswell as the various electrical devices specifically shown in thedrawings. It is also to be understood that the term includes both rotaryconverters and motor generator sets. It is also to be noted in thefollowing specific claims that the designation of a motor part and agenerator part is not intended to designate distinct and separate parts,but means performing the two func tions, as in a rotary converter, aportion of the power is transmitted from the alternating current to thedirect current side by mechanical means and part is merely rectifiedcurrent obtained by means of the commutator, but I intend that motorgenerator sets, as well as rotary converters, are to be included withinthe above terms. V

Fig. 1 shows a motor generator set 1, drawing power from the three-phasealternating current mains 3, 4, and 5, and sup- This is difii-" plyingdirect current to the consumers mains 6 and 7. The load circuits 9, 10and 11 draw a varying amount of current from the mains 6 and 7. Thecontrol mechanism is placed at a central point upon a switchboard S, andsection 13 of which has been indicated on the drawing.

This control mechanism may be at a point remote from the set 1, as theset may be placed in a substation or at any convenient point. I

The excitation of the generator 14 is supplied by the field winding 16and may be initially regulated by a rheostat 17. Current is supplied tothe field winding 16 from the exciter 18, the field 19 of which iscontrolled in accordance with the power drawn from the supply mains. Arheostat 20, having a movable arm 21 is connected in series withthe'field winding 19. The setting of the arm 21 is determined inaccordance with the total amount of power drawn from the supply mains.The manner in which it is accomplished will be readily apparent from thefigures This is accomplished by means of a relay 22 which is actuated inaccordance with the load drawn from the supply mains 3, 4, and 5. Therelay comprises two windings 24 and 25, which are analogous to thewindings of a Watt-meter. This relay is designated the armature relay,in that it is controlled in accordance with the wattage of a circuit towhich it is connected. The contact arm 23, connected to the moving coil24 of the armature relay, is arranged to make contact with the terminals26 and 27. The terminal 26 is connected by wire 28 to a motor 29 and tothe exciter 18. This circuit is closed by the contact arm to vary theresistance of the field 19. A motor 31 is connected in the circuit 30attached to the contact 27. The moving arm 23of the wattmeter relay isconnected by the wire 32'to the other side of the exciter 18. Thevoltage impressed upon the motor generator set may be controlled bythe'reactances 8, connected in the motor leads. storage battery 12 mayform a part of the consumption load circuit and may be an importantelement in regulating the load of certain systems. The motors 29 and 31are connected by suitable gears, not shown, to drive the arm 21.

The operation of the above-described system will be briefly set forth:When the power demanded by the circuits 9, 10 and 11 rises to themaximum value for which the consumer has contracted, it is imperativethat no more current be allowed to flow from the mains 3, 4, 5;otherwise, the extra current would be bought at a greatly advancedprice, or a penalty would be incurred by exceeding the maximum. Therelay 22 which is in effect a Watt-meter is sensitive to the amount ofpower drawn from the supply mains and when the amount approaches themaximum, the arm 23 will be moved to the right and make a Contact withthe terminal 27. The motor 31 rotates the arm 21 to increasethe'resistance of the rheostat 20 and thereby reduces excitation of thefield 19 of the exciter 18. The voltage of the exciter 18 is thusreduced and this,

in turn, reduces the excitation of the gen '11. In certain systems, astorage battery 12 may be employed, and this storage battery will supplythe extra demand for current, so that the consumption of current in'thepower circuits 9, 10 and 11 may greatly exceed at this time the powerdrawn from the mains 3, 4, and 5. Upon the decreased de-' mand in theload circuits 9, 10 and 11, the Wattmeter relay 22 will indicate thelower rate of energy being drawn from the mains and, as a consequence,will close a circuit at the terminal 26. The motor 29 is then operatedto decrease the resistance of the rheostat 20 and to increase theexcitation of the exciter 18. This raises the voltage of the generator14 and the consequent flow of current through the load circuits will bein creased. If this is not demanded, however,

the surplus current will flow into the storage battery 12 to charge thesame. In-this manner, the load upon the supply mains 3, 4, and5 will bemaintained substantially at a constant value, even under considerablevariations of the load drawn from the consumption mains 6, 7

The power consumed may be j'measured. on the consumption side of thetransforming device as well as upon the supply side. The watt-meter isconnected in the direct current side of the motor generator set 1. Theaction is the same as when the wattmeter is connected to the line sideof the generator set except that it does not include the transformationlosses.

In the manner above described, I am enabled to-control the power drawnby a number of substations or by a number of units in the samesubstation. In Fig. 2 I have shown two transforming units 40- and 41connected to the supply mains 3, 4 and 5. The transforming units 40 and41 are illustrated as rotary converters, but it is evident that the samemight be other apparatus, such as motor generator sets, frequencychangers, etc.

The current coil 24 of the wattmeter relay is connected in series to thecoils 42 and 43 of the corresponding current transformers 44 and 45,which are connected the leads :of the transformer units 40 and 4:1 andwhich indicate the current flowing to said units. The voltage coil ofthe wattmeter relay is connected across the phase 4, 5 of the mains andindicates the voltage impresed upon the transformer units. The movingcoil 24 operates the moving contact 23 in the manner indicated inconnection with Fig. 1. The units 40 and 41 are excited by current fromany exciter 18, which is controlled in accordance with the total powerreceived by the two transforming units to vary simultaneously thevoltage generated and supplied to the consumption mains 6 and 7 tomaintain a uniform load upon the supply mains. It is not essential to myinvention that both of theunits 40 and 41 be connected to the sameconsumption circuit and it is not essential that the voltage of both ofthe transforming devices be thus controlled. Such a condition may bebrought about by merely omitting any connection done of the translatingdevices with the regulating means, or in other words, utilizing anordinary translating means to feed another branch or consumers circuit.

In Fig. 3 a system of load regulation similar to the systems showninFigs. 1 and 2 is illustrated. A number of transforming units 50, 51 and52, are supplied with current from the mains 3, -l and 5 and delivercurrent to the consumption mains 6,7, which, in this case, have beenillustrated as separate service mains for each transforming unit. Thefield excitation for the transforming units is supplied by fieldwindings 16 connected to the mains of the exciter .18. The current inthese field windings is simultaneously regulated by varying the voltageof the exciter. Resistances 17 may be placed in the circuits of thefield windingto secure the proper initial adjustment ofthe excitationof/the transforming units.

The reactances 8 are inserted in the leads primarily for protection asfor preventing surges and more particularly for limiting short circuitcurrent. trated in Fig. 2 the reactances 8 are used in connection withthe change of field excitation to control the voltage.

The wattmeter relay in this case comprises a stationary voltage winding25 and a plurality of movable windings 58, 59 and 60 which, in thiscase, have been illustrated as separate coils mounted on a commonspindle.

The coil 58 is connected to the secondary of the series transformer 55which transformer is affected by the current drawn by the transformingunit 50. Coil 59 of the wattmeter relay is connected to the secondary ofthe current transformer 56 and is affected by the current drawn by thetransforming unit 51, Coil 60 is connected to the In the system illussecondary of the series transformer 57 which is affected by the currentdrawn by transforming unit 52. The relation of the current and thevoltage coils in the wattmeter relays is such that this relay isactuated at all times in accordance with the actual power drawn by thetransforming units, that is, it is actuated in accordance with wattsconsumed instead of volt-amperes. The transformer relay 22 is providedwith a movable contact 23 playing between the contacts 26 and 27 andcontrols thefield resistance 20 of exciter 18 in the manner described inconnection with Figs. 1 and 2.

Instead of having a single exciter generator 18 I may employ an exciterat each one of the substations and may control the field circuits bymeans of the pilot wires 28, 30

and 32 running from the central station to the individual substationsinstead of running the leads from the generator 18 to the varioussubstations. This requires substantially a duplication of the systemshown in Fig. 1. As very little current would be carried by the pilotwires 32, 30 and 28, a saving in copper in this construction would bevery considerable. It is understood, of course, that each one of the.exciters 18 would have a rheostat 2O controlled by motors 31 and 29 andthe effect of closing the circuits through the pilot wires would be tooperate all the rheostats simultaneously.

The operation of this system is the same as described in connection withFig. 2. It will be seen in connection with this system that the loadtaken by one unit may compensate to a degree for the load carried by theother. The watt-meter relay will not operate to cut down the voltage ofthe consumers side of the system until there is danger of exceeding themaximum demand. The summation or integration of the loads' taken by thevarious pieces of apparatus is suitably performed by the watt-meterrelay 22. A pointer and scale readings may also be provided for thisrelay in order to indicate at all times the amount of power taken fromthe main.

The system above described is especially applicable to power systemswhere a decrease in voltage serves merely to slow down the entire systemwithout causing any considerable inconvenience. The invention abovedescribed is applicable not onlyto systems converting alternatingcurrent to direct current but to any type of system employing thetransforming unit, the secondary side of which is capable of voltagecontrol.

While the invention has been described with reference to the particularsof certain systems, it is not intended thereby to limit the invention toany particular system, but, instead, I consider the above system of loadregulation to be broadly new and desire that the claims be interpretedin the broadest sense of which they are capable.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a system of load regulation, supply mains, a plurality oftransforming units, leads connecting said transforming units to saidsupply mains, consumption circuits supplied by said transforming units,current transformers in said leads and a wattmeter relay having a coilconnected in series with the secondaries of said current transformers,circuits controlled by said relay for simultaneously varying the fieldexcitation of said plurality of said transforming units to vary thevoltage impressed upon said consumption circuits.

2. In a system of load regulation, supply mains, a plurality oftransforming units, leads connecting said transforming units to saidsupply mains, consumption circuits supplied by said transforming units,current transformers in said leads and a watt-meter relay having amoving element controlled by the combined action of said current transformers, circuits controlled by said relay for simultaneously varyingthe field excitation of said transforming units to vary the voltageimpressed upon said consumption circuits.

3. In a system of load regulation, alternating current supply mains,supply branches connected thereto, current translators connected to saidsupply branches, direct current work circuits connected to saidtranslators and receiving current therefrom, means to excite thetranslators, a watt meter relay to control said means, said relay havingits voltage coils shunted across the mains, and its current coilsinterposed in the supply branches to each translator, whereby theaggregate current consumed by the work circuits through the translatorsmay act upon the current coils of said relay, such action being obtainedby the integration of loads on said work circuits.

4. In a system of load regulation, the combination of alternatingcurrent supply mains, supply branches connected thereto, currenttranslators connected to the branches, direct current work circuitsconnected to said translators and receiving current therefrom, excitingmeans for the translators, a watt meter relay having voltage and currentcoils, the former connected to the mains and the latter to the branches,a variable resistance to control the strength of excitatrolling saidresistance.

both in voltage and amperage of the mains to control the regulator, saidmeans being connected to said regulator to continuously control the sameregardless of the degree of change of load or the direction in whichsuch change takes place on the consum tion circuits so as to maintainthe wattage t ereof constant.

7 In a system of distribution, the combination of a generator, supplymains, means to drive the generator, means to regulate the generator,means sensitive to changes both of voltage and amperage of said mainsand having connection with the regulator to control the same, andthereby maintain constant the wattage derived from the generatorregardless of variation in load imposed thereon.

8. In a system of distribution, the combination of a generator, means todrive the same, automatic means to regulate the generator, and meanscontrolling the regulator and responsive to changes both of the voltagethe generator constant regardless of change in load imposed thereon.

9. In a system of distribution, the combination of mains, a generator,means to drive the generator, means to regulate the generator, meanssensitive to changes both of voltage and amperage of said mains andhaving connection with the regulator to control the same, and therebymaintain constant the wattage derived from the generator regardless ofvariation in load imposed thereupon, and auxiliary consumption andsupply means in the work circuit.

In witness whereof, I hereunto subscribe my name this 18th day of July,A. D. 191.4.

WILLIAM L. WATERS.

. Witnesses:

O. W. CAMPBELL,

Gno. J. CAMPBELL.

